I. Field of the Invention
The present invention relates generally to conveyors and, more particularly, to a lift and carry accumulating conveyor.
II. Description of the Prior Art
There are a number of previously known lift and carry conveyors for transporting various types of parts along a conveyor line. These previously known lift and carry conveyors typically comprise a pair of spaced apart and parallel stationary rails which engage and support the part to be conveyed, such as a piston connecting rod. Additionally, a pair of transfer rails extend along the conveyor line in between the stationary rails.
These transfer rails, unlike the stationary rails, are movable both between an upper and lower position, as well as a forward and retracted position. When moved to their upper position, the transfer rails lift the part being conveyed up off of the stationary rail. When in their raised position, movement of the transfer rails to their forward position simultaneously carries the part by a distance defined by the stroke of the transfer rails between the forward and retracted position.
Once the transfer rails are in their forward position, the transfer rails are moved to their lower position again depositing the parts on the stationary rail. The transfer rails are then moved to their retracted position and the above process is continuously repeated.
In the event of a part stoppage on the conveyor line, the parts merely accumulate on the conveyor line during which time the transfer rails, when moved from their retracted to forward position merely slide along the bottom of the conveyed
Although linear sections of the previously known lift and carry conveyors have functioned adequately, certain difficulties have been encountered when the conveyor system includes an arcuate section. Such an arcuate section would be necessary, for example, when necessary to change the direction of the conveyor line.
With the previously known lift and carry conveyors, the arcuate sections were simply constructed with the stationary rails. Thus, in operation, the parts would accumulate on the stationary rail and simply be pushed by the incoming parts around the arcuate conveyor section and through the subsequent conveyor section.
One disadvantage of these previously known arcuate sections, however, is that a relatively high pressure is imposed upon the parts through the arcuate section. In some cases, this pressure imposed upon the parts is sufficient to eject the part from the conveyor section. In other cases, jamming of the conveyor line has resulted. This jamming was due to the curved portion alignment of the conveyor line to the straight section.